In vehicle transmissions the oil level existing in the transmission oil sump varies due to the dynamics of the vehicle, in particular due to speed changes. In extreme driving situations such as an ABS braking process, or when starting off with maximum acceleration or when cornering at high speed, the oil level in the transmission oil sump can vary to an extent which, disadvantageously, results in undesired introduction of air.
From DE 7304197 U an oil sump accessory for blocking through-flow passages by means of a back-flow of oil is known, which comprises a plate with a plurality of openings in which check-flaps are provided, to close the openings. In this way the oil below the accessory is retained and introduction of air by the oil pump in the transmission oil sump is avoided.
With this design situations can arise in which, due to extreme accelerations, the oil collects axially in one part of the transmission oil sump, and this in turn can lead to air introduction.
From JP 2005248991 A, a transmission oil sump is known, in which a baffle plate is provided which defines a main transmission oil compartment and an adjoining transmission oil compartment, and the transmission oil sump has a rotating component arranged in the adjoining transmission oil compartment. In this case the baffle plate is designed in such manner that it enables oil to flow from the adjoining transmission oil compartment into the main transmission oil compartment by virtue of a pumping action produced by the rotating component.
Disadvantageously, the design known from JP 20055248991 A entails higher costs and greater effort for its production and assembly.
From DE 1927174 A, a means for maintaining the oil level in a sump is known, comprising baffles arranged transversely to the driving direction, in which a baffle provided with one or more openings, extends to a height substantially above the oil level when the motor is horizontal, and is in close contact with the bottom and sidewalls up as far as a residual opening that acts as a bypass. In this case the openings can be blocked by a movable flap with a horizontal pivot axis at the top, arranged on the side of the baffle that faces toward the oil inlet grid. With this design oil can disadvantageously flow through the residual opening, particularly during prolonged situations of rapid vehicle deceleration or acceleration, and this too can result in the introduction of air.